Color conversion method and profile generation method

ABSTRACT

A tincture adjustment value used to adjust a monochrome signal to a tincture desired by a user is set, and a tincture conversion table and chromaticity line table are generated based on that tincture adjustment value and the profile of an image output apparatus. Using the generated tables, a lightness signal L* corresponding to an input monochrome signal is converted into a distance signal l on a chromaticity line, and the distance signal l is converted into a chromaticity signal (a*, b*). The lightness signal L* and chromaticity signal (a*, b*) are converted into a color signal of the image output apparatus.

This application is a continuation of U.S. patent application Ser. No.10/531,062, which was the National Stage of International ApplicationNo. PCT/JP2004/001145, filed Feb. 4, 2004, the contents of which areincorporated by reference herein.

TECHNICAL FIELD

The present invention relates to a technique for converting an inputmonochrome signal into color signals of an image output apparatus.

BACKGROUND ART

In recent years, use of digital color images has increased abruptlyalong with the popularization of digital cameras. Photo print techniquesfor satisfactorily printing these images have been extensivelydeveloped. On the other hand, in the field of silver halide photos, ithas been prevalent to take monochrome photos using vintage cameras.Monochrome photos, unlike color photos, express an object's texture bysubtle flavor and expressive power, and are used as an expressive meansdifferent from that of color photos. Digital monochrome images are notso currently prevalent compared to color photos. If digital cameras areused to produce expressive images of the same sort as monochrome silverhalide photos in the future, however, expansion of the usage of digitalmonochrome images is expected.

In general, a monochrome image is printed by forming an image using ablack color agent (ink or toner). When an image is formed using a blackcolor agent alone, however, the color characteristics of the black coloragent practically determine the tincture of a printed image. Hence, thetincture of a printed image cannot be controlled in order to bereproduced desirably.

A monochrome image is also often formed by a so-called “compositeblack”, using color agents such as, inter alia, cyan (hereinafterabbreviated as C), magenta (hereinafter abbreviated as M), yellow(hereinafter abbreviated as Y), in addition to black (hereinafterabbreviated as K). In these cases, by combining color agents at anappropriate ratio, the tincture of a monochrome image can be desirablyreproduced. Also, by changing the ratio of combined color agents, thetincture can be adjusted.

Furthermore, when a color printer is used to print a monochrome image,the tincture cannot be adjusted unless the printer has a specialadjustment function. Hence, when a monochrome image is outputted with adesired tincture, image data is converted into R, G, and B colorcomponent signals, which are to be adjusted.

In the above prior art, however, when the tincture is adjusted byadjusting the color agent amounts or color component signal values,because the relationship between the adjustment amounts and print colorsis not always constant, an unexpected adjustment result is oftenobtained. Some adjustments may also lose a tincture balance at aspecific gray level, and the tincture may appear in somedisproportionate fashion. For example, when a tinge of yellow is to beenhanced by increasing the amount of a Y color agent or decreasing a Bsignal value, the tincture of middle lightness has nearly no change, butan image with excessively yellowish highlighting may be formed.Furthermore, some adjustments may often change the brightness of animage.

DISCLOSURE OF INVENTION

The present invention has been made to solve the aforementionedproblems, and has as its object to generate a profile used to print amonochrome image with a tincture of the user's choice without any colordeviation.

It is another object of the present invention to convert monochromeimage data into color image data that can be printed with a desiredtincture without biasing colors upon printing the monochrome image databy a designated image output apparatus.

In order to achieve the above objects, according to one aspect of thepresent invention, there is provided a color conversion method forconverting an input monochrome signal into a color signal on apredetermined color space, comprising: a setting step of setting atincture adjustment value used to adjust the input monochrome signal toa desired tincture of a user; an acquisition step of acquiring colorreproduction characteristics which depend on an image output apparatusand a recording medium; a first conversion step of converting the inputmonochrome signal into a first color signal using the color reproductioncharacteristics acquired in the acquisition step; a second conversionstep of converting the first color signal converted in the firstconversion step into a second color signal using the tincture adjustmentvalue set in the setting step and the color reproduction characteristicsacquired in the acquisition step; a third conversion step of convertingthe second color signal converted in the second conversion step into athird color signal; and an output step of forming and outputting a colorsignal on the color space on the basis of the third color signalconverted in the third conversion step and the first color signalconverted in the first conversion step.

According to one aspect of the present invention, there is provided aprofile generation method for generating a profile which stores arelationship between monochrome signals and color signals on apredetermined color space, comprising: a setting step of setting atincture adjustment value used to adjust monochrome signals to a desiredtincture of a user; an acquisition step of acquiring color reproductioncharacteristics which depend on an image output apparatus and arecording medium; a generation step of generating discrete monochromesignals; a first conversion step of converting the monochrome signalsgenerated in the generation step into first color signals using thecolor reproduction characteristics acquired in the acquisition step; asecond conversion step of converting the first color signals convertedin the first conversion step into second color signals using thetincture adjustment value set in the setting step and the colorreproduction characteristics acquired in the acquisition step; a thirdconversion step of converting the second color signals converted in thesecond conversion step into third color signals; and a profilegeneration step of generating a profile on the basis of the third colorsignals converted in the third conversion step and the first colorsignals converted in the first conversion step.

According to one aspect of the present invention, there is provided animage conversion method for converting input monochrome image data intocolor image data for an image output apparatus designated by a user,comprising: a setting step of setting a tincture adjustment value usedto adjust the input monochrome image data to a desired tincture of auser; an acquisition step of acquiring color reproductioncharacteristics which depend on the image output apparatus and arecording medium; a first conversion step of converting monochromesignals which form the input monochrome image data into first colorsignals using the color reproduction characteristics acquired in theacquisition step; a second conversion step of converting the first colorsignals converted in the first conversion step into second color signalsusing the tincture adjustment value set in the setting step and thecolor reproduction characteristics acquired in the acquisition step; athird conversion step of converting the second color signals convertedin the second conversion step into third color signals; and a conversionstep of converting the third color signals converted in the thirdconversion step and the first color signals converted in the firstconversion step into color image data for the image output apparatus,and outputting the color image data.

According to one aspect of the present invention, there is provided animage processing apparatus for converting an input monochrome signalinto a color signal on a predetermined color space, and outputting thecolor signal, comprising: setting means for setting a tinctureadjustment value used to adjust the input monochrome signal to a desiredtincture of a user; acquisition means for acquiring color reproductioncharacteristics which depend on an image output apparatus and arecording medium; first conversion means for converting the inputmonochrome signal into a first color signal using the color reproductioncharacteristics acquired by the acquisition means; second conversionmeans for converting the first color signal converted by the firstconversion means into a second color signal using the tinctureadjustment value set by the setting means and the color reproductioncharacteristics acquired by the acquisition means; third conversionmeans for converting the second color signal converted by the secondconversion means into a third color signal; and output means for formingand outputting a color signal on the color space on the basis of thethird color signal converted by the third conversion means and the firstcolor signal converted by the first conversion means.

According to one aspect of the present invention, there is provided animage processing apparatus for generating a profile which stores arelationship between monochrome signals and color signals on apredetermined color space, comprising: setting means for setting atincture adjustment value used to adjust monochrome signals to a desiredtincture of a user; acquisition means for acquiring color reproductioncharacteristics which depend on an image output apparatus and arecording medium; generation means for generating discrete monochromesignals; first conversion means for converting the monochrome signalsgenerated by the generation means into first color signals using thecolor reproduction characteristics acquired by the acquisition means;second conversion means for converting the first color signals convertedby the first conversion means into second color signals using thetincture adjustment value set by the setting means and the colorreproduction characteristics acquired by the acquisition means; thirdconversion means for converting the second color signals converted bythe second conversion means into third color signals; and profilegeneration means for generating a profile on the basis of the thirdcolor signals converted by the third conversion means and the firstcolor signals converted by the first conversion means.

According to one aspect of the present invention, there is provided animage processing apparatus for converting input monochrome image datainto color image data for an image output apparatus designated by auser, and outputting the color image data, comprising: setting means forsetting a tincture adjustment value used to adjust the input monochromeimage data to a desired tincture of a user; acquisition means foracquiring color reproduction characteristics which depend on the imageoutput apparatus and a recording medium; first conversion means forconverting monochrome signals which form the input monochrome image datainto first color signals using the color reproduction characteristicsacquired by the acquisition means; second conversion means forconverting the first color signals converted by the first conversionmeans into second color signals using the tincture adjustment value setby the setting means and the color reproduction characteristics acquiredby the acquisition means; third conversion means for converting thesecond color signals converted by the second conversion means into thirdcolor signals; and conversion means for converting the third colorsignals converted by the third conversion means and the first colorsignals converted by the first conversion means into color image datafor the image output apparatus, and outputting the color image data.

Other features and advantages of the present invention will be apparentfrom the following description taken in conjunction with theaccompanying drawings, in which like reference characters designate thesame or similar parts throughout the figures thereof.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view for explaining an overview of a color management system(CMS);

FIG. 2 is a block diagram showing an example of an image output systemusing a CMS;

FIG. 3 is a block diagram showing the basic arrangement of an imageprocessing apparatus in the first embodiment;

FIG. 4 is a block diagram showing the functional arrangement of theimage processing apparatus in the first embodiment;

FIG. 5 shows an example of grayscale characteristics stored in agrayscale characteristic holding module 408;

FIG. 6 shows an example of the relationship between a monochrome signalGL and lightness L*;

FIG. 7 shows an example of a tincture conversion table stored in atincture conversion table holding module 409;

FIG. 8 illustrates a chromatic point path projected onto an a*b*chromaticity plane on the CIELAB color space;

FIG. 9 shows an example of the relationship between lightness values L*and distance signals 1, which form the tincture conversion table shownin FIG. 7;

FIG. 10 shows an example of a chromaticity line table stored in achromaticity line table holding module 410;

FIG. 11 shows an example of a UI used to set a gray chromaticity point;

FIG. 12 shows an example of a UI used to a chromaticity point changerate;

FIG. 13 is a flow chart showing the profile generation sequence in thefirst embodiment;

FIG. 14 is a block diagram showing the functional arrangement of animage processing apparatus in the second embodiment;

FIG. 15 shows an example of an output profile stored in an outputprofile holding module 1410;

FIG. 16 shows an example of a color patch image in the secondembodiment;

FIG. 17 is a flow chart showing the image processing sequence in thesecond embodiment;

FIG. 18 is a block diagram partially showing the functional arrangementof the image processing apparatus in a modification of the first andsecond embodiments;

FIG. 19 is a block diagram showing the arrangement of an imageprocessing apparatus and its peripheral devices in the third embodiment;

FIG. 20 is a block diagram showing the basic arrangement of an imageprocessing apparatus 1900 in the third embodiment;

FIG. 21 is a block diagram showing the functional arrangement of animage processing unit 1920 shown in FIG. 19;

FIG. 22 shows an example of an output profile stored in an outputprofile holding module 2110;

FIG. 23 shows an example of a color separation LUT stored in a colorseparation LUT holding module 2111;

FIG. 24 is a flow chart showing the image processing sequence in thethird embodiment;

FIG. 25 shows an example of a UI used to set a gray chromaticity pointin a modification;

FIG. 26 shows an example of a UI used to set a change rate of achromaticity point in a modification; and

FIG. 27 is a block diagram showing the functional arrangement of animage processing unit in a modification of the third embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments of the present invention will be described indetail hereinafter with reference to the accompanying drawings.

[First Embodiment]

The first embodiment will exemplify an image processing apparatus whichgenerates a profile used to print an input monochrome image in a desiredcolor without any tincture deviation in a print process using a colormanagement system (hereinafter referred to as a CMS).

<CMS>

FIG. 1 is a view for explaining an overview of the CMS. The CMS isprimarily a color processing technique that allows a plurality of imageinput/output apparatuses (e.g., a color copy 101, color monitor 102,digital camera 103, color printer 104, and the like) to satisfactorilyreproduce an identical color image. According to the CMS, a color signalof an input system is converted into that of an output system. Morespecifically, an input color signal depending on an input systemapparatus is converted into a signal on a color match color space, whichis independent of any apparatuses using a predetermined conversionformula or table that pertains to the input system apparatus. Thepredetermined conversion formula or table used to mutually convert asignal on the color space depending on a given apparatus and a signal onthe color match color space in this way is called a “profile” of thatapparatus. The converted signal on the color match color space undergoesa predetermined color process to obtain a signal value to be output. Thesignal value is then converted into a signal on a color space dependingon each apparatus of an output system with reference to a profile ofthat apparatus.

As described above, according to the CMS, because a color signal isconverted between the color space depending on each apparatus and thecolor match color space, color matching among a plurality of apparatusescan be realized.

FIG. 2 is a block diagram showing an example of an image output systemusing the CMS. In the image output system shown in FIG. 2, R, G, and Bcolor signals that form image data are converted into C, M, Y, and Kcolor signals of a connected image output apparatus by an input profileconversion unit 201, color mapping unit 202, output profile conversionunit 203, and color separation conversion unit 204.

The input profile conversion unit 201 converts input R, G, and B colorsignals into L*, a*, and b* color signals on a CIELAB color space on thebasis of the profile which is stored in an input profile storage unit205 and represents the color reproduction characteristics of an imageinput apparatus. The input profile storage unit 205 stores L*, a*, andb* color signals corresponding to discrete R, G, and B color signals asa three-dimensional (3D) lookup table (to be abbreviated as an LUThereinafter). The input profile conversion unit 201 converts the inputR, G, and B color signals into L*, a*, and b* color signals on theCIELAB color space by a known method using that 3D LUT.

The color mapping unit 202 converts L, a, and b input signals into L′,a′, and b′ color signals which can be reproduced by the image outputapparatus. In this way, when the image input apparatus and image outputapparatus have different color gamuts, the color mapping unit 202 canabsorb their differences. When the image input apparatus and imageoutput apparatus have equal color gamuts, the input color signals aredirectly output.

The output profile conversion unit 203 converts input L′, a′, and b′color signals into R′, G′, and B′ color signals depending on the imageoutput apparatus on the basis of a profile which is stored in an outputprofile storage unit 206 and represents the color reproductioncharacteristics of the image output apparatus. Note that the outputprofile storage unit 206 typically stores L′, a′, and b′ color signalscorresponding to discrete R′, G′, and B′ color signals as a 3D LUT. Theoutput profile conversion unit 203 searches that 3D LUT for data nearthe input L′, a′, and b′ color signals, and calculates output R′, G′,and B′ color signals on the basis of the found data and the input colorsignals using a known interpolation method.

The color separation conversion unit 204 converts the input R′, G′, andB′ color signal into output C, M, Y, and K color signals by a knownmethod using a color separation LUT stored in a color separation LUTstorage unit 207. Then, a print image corresponding to the input imagedata is formed by the image output apparatus (not shown) on the basis ofthe C, M, Y, and K color signals.

In this way, in the image output system using the aforementioned CMS,each of print colors corresponding to the input image data is determinedby the input profile stored in the input profile storage unit 205. Theimage processing apparatus of the first embodiment generates an inputprofile used to print a monochrome image with a tincture of user'schoice without any tincture deviation upon printing that monochromeimage in the image output system using the CMS.

<Basic Arrangement>

FIG. 3 is a block diagram showing the basic arrangement of the imageprocessing apparatus in the first embodiment. Referring to FIG. 3,reference numeral 301 denotes a CPU, which controls the overallapparatus using programs and data stored in a RAM and ROM (to bedescribed below), and also executes image processes (to be describedlater). Reference numeral 302 denotes a RAM which comprises an area fortemporarily storing programs and data loaded from an external storagedevice or recording medium drive, and various data whose processes areunderway, and also a work area used when the CPU 301 executes respectiveprocesses. Reference numeral 303 denotes a ROM which stores programs,control data, and the like required to control the overall apparatus.

Reference numeral 304 denotes an operation unit, which comprises akeyboard and a pointing device such as a mouse, and can input, amongothers, a gray tincture adjustment instruction, output profiledesignation, to this apparatus (to be described later). Referencenumeral 305 denotes a display unit which comprises a CRT, liquid crystaldisplay, etc, and displays various adjustment user interfaces (UIs; tobe described later), images, and text. Reference numeral 306 denotes anexternal storage device which saves an operating system (OS), and animage processing program 307 and parameters 308 required to implementvarious image processes. Reference numeral 309 denotes a recordingmedium drive, which reads various data including image data from arecording medium, and outputs them to the external storage device 306and RAM 302. Also, the storage medium drive 309 saves a generatedprofile. Reference numeral 310 denotes a bus which interconnects theaforementioned units.

<Functional Arrangement>

FIG. 4 is a block diagram showing the functional arrangement of theimage processing apparatus in the first embodiment. As shown in FIG. 4,the apparatus comprises, as the functional arrangement, a color signalgeneration module 401, grayscale characteristic conversion module 402,tincture conversion A module 403, tincture conversion B module 404,format module 405, profile acquisition module 406, tincture adjustmentvalue setting module 407, grayscale characteristic holding module 408,tincture conversion table holding module 409, and chromaticity linetable holding module 410.

In this arrangement, the color signal generation module 401 generatesdiscrete monochrome signals GL. The grayscale characteristic conversionmodule 402 converts the monochrome signals GL into print image lightnessvalues L*, obtained when the monochrome signals GL are output by theimage output apparatus on the basis of grayscale characteristics storedin the grayscale characteristic holding module 408.

FIG. 5 shows an example of the grayscale characteristics stored in thegrayscale characteristic holding module 408. The grayscalecharacteristics are stored as a correspondence table of lightness valuesL* in association with discrete monochrome signals GL, and areassociated print image with brightness. Note that a lightness value L*corresponding to an arbitrary monochrome signal GL is calculated by aknown interpolation operation on the basis of the grayscalecharacteristics.

FIG. 6 shows an example of the relationship between the monochromesignal GL and lightness L*. Referring to FIG. 6, the monochrome signalGL is an 8-bit signal. Lmax represents a lightness value L* whichnormally corresponds to a maximum value (to be referred to as a whitesignal hereinafter) GL=255 of the monochrome signal GL, and Lminrepresents a lightness value L* which corresponds to a minimum value (tobe referred to as a black signal) GL=0 of the monochrome signal GL. Thevalues Lmax and Lmin are acquired by the profile acquisition module 406(to be described later). A lightness value L* corresponding to amonochrome signal GL which meets 0<GL and GL<255 is preferablydetermined on the basis of the values Lmax and Lmin and desiredgrayscale characteristics.

The tincture conversion A module 403 converts each lightness value L* asan input signal into a distance signal 1 on a chromaticity space (to bedescribed later) on the basis of a tincture conversion table stored inthe tincture conversion table holding module 409.

FIG. 7 shows an example of the tincture conversion table stored in thetincture conversion table holding module 409. This tincture conversiontable is a correspondence table of distance signals 1 in associationwith discrete lightness values L*, and is associated with the tinctureof a print image. A distance signal 1 corresponding to an arbitrarylightness value L* is calculated by a known interpolation operation onthe basis of this tincture conversion table.

The distance signal 1 and a chromaticity point path (gray line) of themonochrome signal in the profile to be generated will be described indetail below using FIG. 8.

FIG. 8 illustrates the chromaticity point path projected onto an a*b*chromaticity plane on the CIELAB color space. Referring to FIG. 8, apoint W is a chromaticity point of a print color (white print color)corresponding to the white signal, and a point K is a chromaticity pointof a print color (black print color) corresponding to the black signal.The chromaticity points (points W and K) of white and black print colorsare acquired by the profile acquisition module 406 (to be describedlater). A point G is a chromaticity point (gray chromaticity point) of amiddle lightness value, which is designated by an adjustment instructionfrom the tincture adjustment value setting module 407 (to be describedlater).

When a profile is generated so that the gray line passes the graychromaticity point (point G) designated by the adjustment instruction,as shown in FIG. 8, a monochrome print image with a tincture based onuser's intention can be obtained.

This distance signal 1 indicates a distance along the gray line when thepoint W is a starting point, and a signal value corresponding to eachchromaticity point on the gray line, as shown in FIG. 8. For example, adistance signal lg corresponding to the point G indicates a distancebetween the points W and G along the gray line, and a distance signal lkcorresponding to the point K indicates the sum of the distance signal lgand a distance between the points G and K along the gray line. Also, adistance signal corresponding to the point W is zero.

Details of the tincture conversion process in the tincture conversion Amodule 403 shown in FIG. 4 will be described below using FIG. 9.

FIG. 9 shows an example of the relationship between the lightness valuesL* and distance signals 1, which form the tincture conversion tableshown in FIG. 7. Referring to FIG. 9, lightness Lmin indicates thelightness value of the black print color. The chromaticity point of thatblack print color is the point K shown in FIG. 8, and a distance signal1 corresponding to lightness Lmin is the distance signal lk in the aboveexample. On the other hand, lightness Lmax is the lightness value of thewhite print color. The chromaticity point of that white print color isthe point W shown in FIG. 8, and a distance signal 1 corresponding tolightness Lmax is zero, as described above. A distance signal 1corresponding to a middle lightness part (L* that satisfies L1<L* andL*<L2 in FIG. 9) is the distance signal lg corresponding to thechromaticity point G shown in FIG. 8. In the first embodiment, bygenerating a profile so that the chromaticity point of the middlelightness part matches the gray chromaticity point (point G shown inFIG. 8) designated by the adjustment instruction, a monochrome printimage with a tincture based on user's intention can be obtained.

Suppression of tincture changes in highlight and shadow parts will bedescribed below using FIG. 9. Referring to FIG. 9, when theaforementioned middle lightness part has a broad lightness range (i.e.,L2-L1 is large) most of input monochrome signals except for highlightand shadow are reproduced based on the chromaticity point (point G shownin FIG. 8) designated by the adjustment instruction. In this case,however, because the change rate of the distance signal 1 associatedwith lightness (i.e., that of the chromaticity point is large in a highlightness part near the white print color and a low lightness part nearthe black print color) tincture changes are observed in, among others,gradation images.

In the first embodiment, since the tincture adjustment value settingmodule 407 (to be described later) issues an adjustment instruction ofthe change rate of the chromaticity point, (1) and 0 (angles linesegments indicated by the tincture conversion table and a straight lineparallel to the L* axis make respectively in the high and low lightnessparts) in FIG. 9 are appropriately set, thus generating a profile whichsuppresses tincture changes of a print image.

The tincture conversion B module 404 shown in FIG. 4 converts eachdistance signal 1 as an input signal into a chromaticity coordinatesignal (a*, b*) on the CIELAB color space on the basis of a chromaticityline table stored in the chromaticity line table holding module 410.

FIG. 10 shows an example of the chromaticity line table stored in thechromaticity line table holding module 410. This chromaticity line tableis formed by extracting the relationship between distance signals 1 onthe gray line shown in FIG. 8 and chromaticity coordinates (a*, b*) inassociation with discrete distance signals 1. A chromatic coordinatesignal (a*, b*) corresponding to an arbitrary distance signal 1 iscalculated by a known interpolation operation on the basis of thischromaticity line table.

The format module 405 converts the input L*, a*, and b* signals into aprescribed format, thus generating a profile. This profile is made up ofa 3D LUT (L*, a*, and b* color signals corresponding to discrete R, G,and B color signals), and various kinds of header information. When R,G, and B color signals have equal color signal values (R=G=B), the 3DLUT stores L*, a*, and b* color signals on the basis of the outputs fromthe grayscale characteristic conversion module 402 and tinctureconversion B module 404 when the color signal generation module 401generates the corresponding monochrome color signals (GL=R=G=B). Forother R, G, and B color signals, the 3D LUT stores dummy L*, a*, and b*color signals.

The profile acquisition module 406 acquires an output profile of theimage output apparatus, and then acquires L*, a*, and b* color signalsof white and black print colors, which depend on that image outputapparatus and an image recording medium (print paper).

The acquired L*, a*, and b* color signals of white and black printcolors are used by the grayscale characteristic holding module 408 andthe tincture adjustment value setting module 407 (to be describedbelow).

The aforementioned tincture adjustment value setting module 407 sets thetincture conversion table to be stored in the tincture conversion tableholding module 409 and the chromaticity line table to be stored in thechromaticity line table holding module 410 on the basis of thechromaticity points of the white and black print colors acquired by theprofile acquisition module 406, and a gray chromaticity point (point Gshown in FIG. 8) and chromaticity point change rate (values associateswith ID and 0 shown in FIG. 9), which are set using the UIs to bedescribed later.

The first embodiment can generate a profile required to obtain amonochrome print image with a tincture based on user's intention, sinceit comprises of means for setting the gray chromaticity point andchromaticity point change rate.

<UI>

FIGS. 11 and 12 show examples of tincture adjustment value setting userinterfaces (UIs) in the first embodiment. FIG. 11 shows an example of aUI used to set the gray chromaticity point. As shown in FIG. 11, this UIincludes a text box 1101 used to set an a* value of the CIELAB colorspace, a text box 1102 used to set a b* value, an OK button 1103, and acancel button 1104. The a* and b* values of the gray chromaticity pointcorresponding to the point G shown in FIG. 8 are input to the text boxes1101 and 1102. When the user selects the OK button 1103, the inputchromaticity point is set, and the corresponding chromaticity line tableand tincture conversion table are respectively stored in thechromaticity line table holding module 410 and tincture conversion tableholding module 409. When the user selects the cancel button 1104, thesetting values are canceled, and the chromaticity line table andtincture conversion table are not updated.

FIG. 12 shows an example of a UI used to set the chromaticity pointchange rate. As shown in FIG. 12, this UI includes a text box 1201 usedto set a chromaticity change rate of a highlight part, a text box 1202used to set a chromaticity change rate of a shadow part, an OK button1203, and a cancel button 1204. A change rate per unit lightness (L*) ofthe aforementioned distance signal 1 is inputted into each text box. LetH_in be the value to be inputted into the text box 1201, and S_in be thevalue to be inputted into the text box 1202. Then, 4:13 and 0 shown inFIG. 9, and H_in and S_in respectively have the following relationships:Φ=tan⁻¹(S_in)θ=tan⁻¹(H_in)

When the user selects the OK button 1203, Φ and θ corresponding to theinput values are set on the basis of the above equations, and thecorresponding tincture conversion table is stored in the tinctureconversion table holding module 409. On the other hand, when the userselects the cancel button 1204, setting values are canceled, and thetincture conversion table is not updated.

<Image Processing Sequence>

FIG. 13 is a flow chart showing the profile generation sequence in thefirst embodiment. This profile generation process is executed in thefollowing sequence.

In step S1301, an output profile is set. In this output profile settingprocess, the output profile of the image output apparatus is acquired,and L*, a*, and b* color signals of white and black print colors, whichdepend on that image output apparatus and an image recording medium(print paper) are acquired. Furthermore, corresponding grayscalecharacteristics are stored in the aforementioned grayscalecharacteristic holding module 408 on the basis of the acquired L valuesof the white and black print colors. In step S1302, tincture adjustmentvalues are set. In this tincture adjustment value setting process, acorresponding tincture conversion table and chromaticity line table arerespectively stored in the aforementioned tincture conversion tableholding module 409 and chromaticity line table holding module 410 on thebasis of the image output apparatus and image recording medium (printpaper or the like), and the gray chromaticity point and chromaticitypoint change rate set by the aforementioned tincture adjustment valuesetting module 407.

In step S1303, the aforementioned color signal generation module 401generates a discrete monochrome signal GL which forms a 3D LUT to bestored in a profile. In step S1304, the aforementioned grayscalecharacteristic conversion module 402 converts the monochrome signal GLinto a lightness value L*. In step S1305, the aforementioned tinctureconversion A module 403 converts the lightness value L* into a distancefunction 1. In step S1306, the aforementioned tincture conversion Bmodule 404 converts the distance function 1 into a chromaticitycoordinate signal (a*, b*) on the CIELAB color space.

It is checked in step S1307 if the processes of all monochrome signalswhich form the 3D LUT of the profile are complete. If signals to beprocessed still remain, the flow returns to step S1303 to repeat theaforementioned processes. On the other hand, if it is determined in stepS1307 that the processes of all signals are complete, the flow advancesto step S1308, the aforementioned format module 405 forms a 3D LUT onthe basis of the chromaticity coordinate signals (a*, b*) obtained instep S1306, and lightness values L* obtained in step S1304 generates aprofile.

As described above, according to the first embodiment, a profile used toprint a monochrome image to have a desired tincture and to be free fromany tincture change in a print process using the CMS can be easilygenerated. More specifically, this embodiment comprises the means forsetting the gray chromaticity point and chromaticity point change rate,and a profile is generated by determining a gray line on the basis ofsetting values. Using this profile, a monochrome print image with atincture based on user's intention can be obtained.

[Second Embodiment]

The second embodiment of the present invention will be described indetail hereinafter with reference to the accompanying drawings.

An image processing apparatus of the second embodiment convertsmonochrome image data into color image data which can be printed with adesired tincture without any color deviation upon printing themonochrome image by a designated image output apparatus. Note that thebasic arrangement of the image processing apparatus in the secondembodiment is the same as that of the first embodiment explained usingFIG. 3, and a description thereof will be omitted.

<Functional Arrangement>

FIG. 14 is a block diagram showing the functional arrangement of theimage processing apparatus in the second embodiment. As shown in FIG.14, the apparatus comprises, as the functional arrangement, a grayscalecharacteristic conversion module 1401, tincture conversion A module1402, tincture conversion B module 1403, output profile conversionmodule 1404, tincture adjustment value setting module 1405, profileacquisition module 1406, grayscale characteristic holding module 1407,tincture conversion table holding module 1408, chromaticity line tableholding module 1409, and output profile holding module 1410.

In this arrangement, monochrome signals GL that form an input monochromeimage are converted into R, G, and B color signals, which are requiredto print the input monochrome image with a desired tincture without anycolor deviation upon printing the monochrome image by a designated imageoutput apparatus, by the grayscale characteristic conversion module1401, tincture conversion A module 1402, tincture conversion B module1403, and output profile conversion module 1404. Note that theaforementioned functional modules—except for the output profileconversion module 1404, profile acquisition module 1406, and outputprofile holding module 1410—have the same functions as those which havethe same names in the first embodiment explained using FIG. 4, thedescription thereof will be omitted.

The output profile conversion module 1404 converts input L*, a*, and b*color signals into R, G, and B color signals depending on the designatedimage output apparatus on the basis of an output profile stored in theoutput profile holding module 1410. Note that the inputted L*, a*, andb* color signals are adjusted to have a desired tincture, and to obscuretincture changes, as has been explained in the first embodiment. Forthis reason, the image output apparatus can print the image data formedby the R, G, and B color signals as an image which has a desiredtincture and inconspicuous tincture changes. Note that the outputprofile stored in the output profile holding module 1410 represents thecolor reproduction characteristics of the image output apparatus, and isacquired by the profile acquisition module 1406.

FIG. 15 shows an example of the output profile stored in the outputprofile holding module 1410. This output profile is a correspondencetable, that is, a so-called 3D LUT of print colors (CIELAB values) inassociation with discrete R, G, and B color signals. The output profileconversion module 1404 searches this 3D LUT for data near the input L*,a*, and b* color signals, and calculates output R, G, and B colorsignals using a known interpolation method on the basis of the founddata and the input signals.

The profile acquisition module 1406 acquires an output profile of thedesignated image output apparatus. This output profile is obtained byprinting a color patch image of discrete R, G, and B color signals,which form the 3D LUT by the image output apparatus, and measuring theprinted color patch image.

FIG. 16 shows an example of the color patch image in the secondembodiment. The color patch image includes color patches of colorsignals, e.g., {R, G, B}={0, 0, 0}, {0, 0, 16}, . . . , {0, 0, 255}, {0,16, 0}, {0, 16, 16}, . . . , {255, 255, 255}. The acquired profile isstored in the output profile holding module 1410, and L*, a*, and b*color signals (colorimetric values of {R, G, B}={255, 255, 255} and {0,0, 0}) of white and black print colors are used in the grayscalecharacteristic holding module 1407 and tincture adjustment value settingmodule 1405.

<Image Processing Sequence>

FIG. 17 is a flow chart showing the image processing sequence in thesecond embodiment. This image process is done in the following sequence.

In step S1701, an initial setting process is made. In the initialsetting process, a corresponding output profile is stored in theaforementioned output profile holding module 1410 in accordance with thedesignated image output apparatus and an image recording medium (printpaper or the like). Also, an input monochrome image is set. In stepS1702, tincture adjustment values are set. In this tincture adjustmentvalue setting process, a corresponding tincture conversion table andchromaticity line table are respectively stored in the aforementionedtincture conversion table holding module 1408 and chromaticity linetable holding module 1409 on the basis of the image output apparatus andimage recording medium (print paper, etc), and the gray chromaticitypoint and chromaticity point change rate set by the aforementionedtincture adjustment value setting module 1405.

In step S1703, the aforementioned grayscale characteristic conversionmodule 1401 converts a monochrome signal GL which forms the inputmonochrome image into a lightness value L*. In step S1704, theaforementioned tincture conversion A module 1402 converts the lightnessvalue L* into a distance function 1. In step S1705, the aforementionedtincture conversion B module 1403 converts the distance function 1 intoa chromaticity coordinate signal (a*, b*) on the CIELAB color space. Instep S1706, the aforementioned output profile conversion module 1404calculates R, G, and B color signals depending on the image outputapparatus on the basis of that chromaticity coordinate signal (a*, b*)and the lightness value L* obtained in step S1703.

It is checked in step S1707 if the processes of all monochrome signalswhich form the input monochrome image are complete. If signals to beprocessed still remain, the flow returns to step S1703 to repeat theaforementioned processes. On the other hand, if the processes of allsignals are complete, this image process ends.

As described above, according to the second embodiment, monochrome imagedata can be converted into color image data which can be printed to havea desired tincture without any color deviation upon printing thatmonochrome image data by the image output apparatus.

[Modification of First and Second Embodiments]

In the first and second embodiments mentioned above, the tinctureconversion A module (403 in FIG. 4, 1402 in FIG. 14) converts thelightness value L* converted by the grayscale characteristic conversionmodule (402 in FIG. 4, 1401 in FIG. 14) into a distance signal 1 on thegray line. Alternatively, the tincture conversion A module may convert amonochrome signal GL into a distance signal 1 without temporarilyconverting it into lightness L*.

FIG. 18 is a block diagram partially showing the functional arrangementof the image processing apparatus in a modification of the first andsecond embodiments. Note that the functional modules other than agrayscale characteristic conversion module 1801, tincture conversion Amodule 1802, and tincture conversion B module 1803 are not shown in FIG.18, and are the same as those in the first and second embodiments.

The tincture conversion A module 1802 in this modification converts amonochrome signal GL which forms an input monochrome image into adistance signal 1. This conversion process converts the monochromesignal on the basis of a table as a correspondence table of distancesignals 1 in association with discrete monochrome signals GL, in thesame manner as in the first and second embodiments.

[Third Embodiment]

The third embodiment of the present invention will be described indetail below with reference to the accompanying drawings.

An image processing apparatus of the third embodiment converts colorsignals that form an input monochrome image into those for a connectedimage output apparatus, and converts them into color signals, whichallow the image output apparatus to print a monochrome image with adesired tincture without any color deviation.

<Arrangement with Peripheral Devices>

FIG. 19 is a block diagram showing the arrangement of an imageprocessing apparatus in the third embodiment and its peripheral devices.As shown in FIG. 19, an image processing apparatus 1900 comprises animage input unit 1910, image processing unit 1920, and image output unit1930. In this arrangement, monochrome image data read from an imagerecording medium 1901 is input via the image input unit 1910. The imageprocessing unit 1920 converts the input monochrome image data into colorsignals for an image output apparatus 1902. The image output unit 1930outputs the converted color signals to the image output apparatus 1902.The image output apparatus 1902 typically comprises a color printerwhich forms an image on a sheet surface by four, i.e., C, M, Y, and Kinks or toners.

<Basic Arrangement>

FIG. 20 is a block diagram showing the basic arrangement of the imageprocessing apparatus 1900 in the third embodiment. Referring to FIG. 20,reference numeral 2001 denotes a CPU, which controls the overallapparatus using programs and data stored in a RAM and ROM (to bedescribed below), and also executes image processes (to be describedlater). Reference numeral 2002 denotes a RAM which comprises an area fortemporarily storing programs and data loaded from an external storagedevice or recording medium drive, and various data whose processes areunderway, and also a work area used when the CPU 2001 executesrespective processes. Reference numeral 2003 denotes a ROM which storesprograms and control data, required to control the overall apparatus.

Reference numeral 2004 denotes an operation unit, which comprises akeyboard and a pointing device such as a mouse or the like, and caninput color characteristic parameters of the image output apparatus 1902and an image recording medium (print paper or the like) and a graytincture adjustment instruction (to be described later) to thisapparatus. Reference numeral 2005 denotes a display unit which comprisesof, inter alia, a CRT, and liquid crystal display, and displays variousadjustment user interfaces (UIs; to be described later), images andtext. Reference numeral 2006 denotes an interface (I/F) which connectsthe image output apparatus 1902 and is used to output data to the imageoutput apparatus 1902. Reference numeral 2007 denotes an externalstorage device which saves an operating system (OS), and an imageprocessing program 2008 and parameters 2009 required to implementvarious image processes. Typically, the image processing program 2008includes a control program of the image output apparatus 1902. Referencenumeral 2010 denotes a recording medium drive, which reads various dataincluding image data from the image recording medium 1901, and outputsthem to the external storage device 2007 and RAM 2002. Reference numeral2011 denotes a bus which interconnects the aforementioned units.

<Functional Arrangement>

FIG. 21 is a block diagram showing the functional arrangement of theimage processing unit 1920 shown in FIG. 19. As shown in FIG. 21, theimage processing unit 1920 comprises a grayscale characteristicconversion module 2101, tincture conversion A module 2102, tinctureconversion B module 2103, output profile conversion module 2104, colorseparation conversion module 2105, and tincture adjustment value settingmodule 2106. The image processing unit 1920 converts monochrome signalsGL which form an input monochrome image into input C, M, Y, and K colorsignals for the image output apparatus 1902.

The grayscale characteristic conversion module 2101 converts monochromesignals GL which form an input monochrome image into lightness values L*of a print image, obtained when the monochrome signals GL are outputtedby the image output apparatus 1902, on the basis of grayscalecharacteristics stored in a grayscale characteristic holding module2107. Note that the grayscale characteristics stored in the grayscalecharacteristic holding module 2107 are the same as those shown in FIG. 5explained in the first embodiment, and the relationship between themonochrome signals GL and lightness values L* is also the same as thatshown in FIG. 6. Hence, a description thereof will be omitted.

The tincture conversion A module 2102 converts each lightness value L*as an input signal into a distance signal 1 on the chromaticity space onthe basis of a tincture conversion table stored in a tincture conversiontable holding module 2108. Note that the tincture conversion tablestored in the tincture conversion table holding module 2108 is the sameas that shown in FIG. 7 described in the first embodiment. Also, thedistance signal 1 and the chromaticity point path (gray line), (are) forexample the chromaticity point path projected onto the a*b* chromaticityplane on the CIELAB color space, and the relationship between lightnessvalues L* and distance signals 1, which form the tincture conversiontable, are the same as those shown in FIGS. 8 and 9, and a descriptionthereof will be omitted.

The tincture conversion B module 2103 converts each distance signal 1 asan input signal into a chromaticity coordinate signal (a*, b*) on theCIELAB color space on the basis of a chromaticity line table stored in achromaticity line table holding module 2109. Note that the chromaticityline table stored in the chromaticity line table holding module 2109 isthe same as that shown in FIG. 10 explained in the first embodiment, anda description thereof will be omitted.

The output profile conversion module 2104 converts input L*, a*, and b*signals into R, G, and B color signals depending on the image outputapparatus 1902 on the basis of an output profile stored in an outputprofile holding module 2110.

FIG. 22 shows an example of the output profile stored in the outputprofile holding module 2110. This output profile is a correspondencetable, that is, a so-called “3D lookup table (LUT)” of print colors(CIELAB values) in association with discrete R, G, and B color signals,and pertains to the color reproduction characteristics of the imageoutput apparatus 1902 and image recording medium (print paper or thelike). The output profile conversion module 2104 searches this 3D LUTfor data near the input L*, a*, and b* color signals, and calculatesoutput R, G, and B color signals using a known interpolation method onthe basis of the found data and the input signals.

The color separation conversion module 2105 converts the input R, G, andB color signals into C, M, Y, and K color signals for the image outputapparatus 1902 on the basis of a color separation LUT stored in a colorseparation LUT holding module 2111.

FIG. 23 shows an example of the color separation LUT stored in the colorseparation LUT holding module 2111. This color separation LUT is acorrespondence table of C, M, Y, and K signals in association withdiscrete R, G, and B color signals, and pertains to the colorreproduction characteristics of the image output apparatus 1902 andimage recording medium (print paper or the like). The color separationconversion module 2105 converts input R, G, and B color signals intooutput C, M, Y, and K color signals by a known method using this colorseparation LUT.

The tincture adjustment value setting module 2106 sets a graychromaticity point (point G shown in FIG. 8) and chromaticity pointchange rate (values associates with 41 and 0 shown in FIG. 9) usingtincture adjustment value setting user interfaces (UIs), and sets thetincture conversion table to be stored in the tincture conversion tableholding module 2108 and the chromaticity line table to be stored in thechromaticity line table holding module 2109. Note that the tinctureadjustment value setting user interfaces (UIs) that are the same asthose shown in FIGS. 11 and 12 described in the first embodiment, and adescription thereof will be omitted.

In this way, in the third embodiment as well, since the graychromaticity point and chromaticity point change rate are set, amonochrome print image with a tincture based on user's intention can beobtained.

<Image Processing Sequence>

FIG. 24 is a flow chart showing the image processing sequence accordingto the third embodiment. This image process is executed in the followingsequence.

In step S2401, an initial setting process is made. In the initialsetting process, a corresponding output profile and color separation LUTare stored in the output profile holding module 2110 and colorseparation LUT holding module 2111 in accordance with the image outputapparatus 1902 and an image recording medium (print paper or the like).Also, defaulted or designated grayscale characteristics are stored inthe grayscale characteristic holding module 2107. Furthermore, an inputmonochrome image is set.

In step S2402, tincture adjustment values are set. In this tinctureadjustment value setting process, a corresponding tincture conversiontable and chromaticity line table are respectively stored in theaforementioned tincture conversion table holding module 2108 andchromaticity line table holding module 2109, on the basis of the imageoutput apparatus 1902 and image recording medium (print paper or thelike), and the gray chromaticity point and chromaticity point changerate set by the aforementioned tincture adjustment value setting module2106.

In step S2403, the aforementioned grayscale characteristic conversionmodule 2101 converts a monochrome signal GL which forms the inputmonochrome image into a lightness value L*. In step S2404, theaforementioned tincture conversion A module 2102 converts the lightnessvalue L* into a distance function 1. In step S2405, the aforementionedtincture conversion B module 2103 converts the distance function 1 intoa chromaticity coordinate signal (a*, b*) on the CIELAB color space.

In step S2406, the output profile conversion module 2104 calculates R,G, and B color signals depending on the image output apparatus 1902 onthe basis of the chromaticity coordinate signal (a*, b*) obtained instep S2405 and the lightness value L* obtained in step S2403. In stepS2407, the color separation conversion module 2105 converts the R, G,and B color signals obtained in step S2406 into output C, M, Y, and Kcolor signals for the image output apparatus 1902, and outputs theconverted signals. It is checked in step S2408 if the processes of allmonochrome signals which form the input monochrome image are complete.If signals to be processed still remain, the flow returns to step S2403to repeat the aforementioned processes.

As described above, according to the third embodiment, the tincture of amonochrome image can be easily adjusted without any tincture changes.More specifically, this embodiment has means for setting a graychromaticity point and chromaticity point change rate, and sets a grayline on the basis of the setting values. As a result, a monochrome printimage with a tincture based on user's intention can be obtained.

[Modification of UI]

A modification of the tincture adjustment value setting user interfaces(UIs) in the first to third embodiments will be described below.

Since the tincture adjustment value setting user interfaces (UIs)explained using FIGS. 11 and 12 have high degrees of freedom, if theyare misused, a desired image cannot be obtained, and an unacceptableresult may be obtained in the worst case. Hence, a modification of theseUIs, which can prevent excessive processes against user's will inadjustment of the tincture of a monochrome image, will be explained.Note that the basic arrangement, functional arrangement, and imageprocessing sequence are the same as those in the third embodiment, and adescription thereof will be omitted.

FIG. 25 shows an example of a UI used to set a gray chromaticity pointin the modification. As shown in FIG. 25, the UI includes eight tincturesetting buttons 2501 to 2508, gray setting map 2509, OK button 2510, andcancel button 2511. Note that the gray setting map 2509 is a grid imagecorresponding to the a*b* plane of the CIELAB color space, and grid A ata position corresponding to a* and b* of the current gray chromaticitypoint is indicated by black. The horizontal direction corresponds to thea* axis, and the vertical direction corresponds to the b* axis. When theblack grid moves rightward, a tinge of red is enhanced; when it movesupward, a tinge of yellow is enhanced; when it moves leftward, a tingeof green is enhanced; and when it moves downward, a tinge of blue isenhanced.

When the tincture setting button 2501 is selected, the black gridposition moves in the right direction to enhance a tinge of red.Likewise, the black grid position moves in the upper right directionupon selection of the tincture setting button 2502; in the upperdirection upon selection of the tincture setting button 2503; in theupper left direction upon selection of the tincture setting button 2504;in the left direction upon selection of the tincture setting button2505; in the lower left direction upon selection of the tincture settingbutton 2506; in the lower direction upon selection of the tincturesetting button 2507; and in the lower right direction upon selection ofthe tincture setting button 2508. The gray chromaticity point (point Gshown in FIG. 8) is then set in a color corresponding to the movedposition. By limiting a setting range, an excessive tincture can beprevented from being set.

On the gray setting map 2509, a region outside the setting range isindicated using another color to be distinguished from the settingrange. When the black grid position is to be moved outside the settingrange by the tincture setting button, an alarm sound is generated toinhibit such movement. When the user selects the OK button 2510, theinput chromaticity point is set, and the corresponding chromaticity linetable and tincture conversion table are respectively stored in thechromaticity line table holding module 2109 and tincture conversiontable holding module 2108. When the user selects the cancel button 2511,the setting value is canceled, and the chromaticity line table andtincture conversion table are not updated. This setting range isdetermined in accordance with the subjective evaluation results ofoutput images corresponding to respective setting values. For example,when images are output while changing the setting values in anappropriate step, and undergo subjective evaluation, the range ofsetting values corresponding to images “accepted” by more than halfevaluators is determined as the setting range.

FIG. 26 shows an example of a UI used to set a chromaticity point changerate in the modification. As shown in FIG. 26, the UI includes a slidebar 2601 used to set a chromaticity change rate of a highlight part, aslide bar 2602 used to set a chromaticity change rate of a shadow part,an OK button 2603, and a cancel button 2604. By moving the respectiveslide bars, the values Φ and θ shown in FIG. 9 are increased/decreased,thus setting the chromaticity change rate. For example, when the slidebar 2601 used to set the chromaticity change rate of a highlight part ismoved to the right, Φ increases; when it is moved to the left, Φdecreases. At this time, by limiting a setting range, an excessivetincture can be prevented from being set. In the example shown in FIG.26, the setting range of the slide bar 2601 used to set the chromaticitychange rate of a highlight part is limited to a range from B to C.Likewise, the setting range of the slide bar 2602 used to set thechromaticity change rate of a shadow part is limited to a range from Dto E.

Upon selection of the OK button 2603, Φ and θ are set on the basis ofthe slide bar positions, and a corresponding tincture conversion tableis stored in the tincture conversion table holding module 2108. Uponselection of the cancel button 2604, setting values are canceled, andthe tincture conversion table is not updated. This setting range isdetermined according to the subjective evaluation results of outputimages corresponding to respective setting values.

According to the arrangement of the modification, since the settingranges of the gray chromaticity point and chromaticity point change rateare limited upon setting the tincture of a monochrome image, anexcessive process against user's will can be prevented.

[Modification of Third Embodiment]

<Default Value and Setting Range>

Default values and setting ranges of the aforementioned graychromaticity point and chromaticity point change rate may be set. Thedefault values and setting ranges may be held in correspondence withrespective image recording media (print paper or the like). In thiscase, the tincture adjustment value setting module 2106 in FIG. 21 isused to store these default values and setting ranges.

<Save Setting Value>

The setting values of the gray chromaticity point and chromaticity pointchange rate may be saved. In such cases, the tincture adjustment valuesetting module 2106 in FIG. 21 is used to store the setting values.Also, the setting values may be registered in a list, and by selecting aregistered setup from the list, setting values corresponding to theselected setup may be re-used.

Note that <default value and setting range> and <save setting value>mentioned above may be applied as modifications of the first and secondembodiments in addition to the third embodiment.

<Tincture Conversion A Module>

The aforementioned tincture conversion A module 2102 converts alightness value L* into a distance signal 1 on the gray line.Alternatively, the tincture conversion A module may convert a monochromesignal GL into a distance signal 1 without temporarily converting itinto lightness L*.

FIG. 27 is a block diagram showing the functional arrangement of animage processing unit in the modification of the third embodiment. Asshown in FIG. 27, the image processing unit of this modificationcomprises of grayscale characteristic conversion module 2701, tinctureconversion A module 2702, tincture conversion B module 2703, outputprofile conversion module 2704, color separation conversion module 2705,and tincture adjustment value setting module 2706. This image processingunit converts monochrome signals GL which form an input monochrome imageinto input C, M, Y, and K color signals for the image output apparatus1902.

The tincture adjustment setting module 2706 of this modification sets achange rate of a distance signal 1 in association with a monochromesignal GL, that is, a chromaticity point change rate, using theaforementioned UI, and stores a tincture conversion table correspondingto that change rate in a tincture conversion table holding unit 2708.The tincture conversion A module 2702 converts each monochrome signal GLwhich forms an input monochrome image into a distance signal 1 on thebasis of the tincture conversion table stored in the tincture conversiontable holding module 2708. Other functional modules have the have thesame functions as those which have the same names in the thirdembodiment.

According to the modification of the third embodiment, tinctureadjustment can be done independently of grayscale conversion.

As described above, according to the third embodiment and itsmodification, the tincture of a print color can be easily adjusted to befree from any tincture deviation and to obscure tincture changes.

Note that the present invention may be applied to either a systemconstituted by a plurality of devices (e.g., a host computer, interfacedevice, reader, printer, and the like), or an apparatus consisting of asingle equipment (e.g., a copying machine, facsimile apparatus, or thelike).

The objects of the present invention are also achieved by supplying arecording medium, which records a program code of a software programthat can implement the functions of the above-mentioned embodiments tothe system or apparatus, and reading out and executing the program codestored in the recording medium by a computer (or a CPU or MPU) of thesystem or apparatus.

In this case, the program code itself reads out from the recordingmedium implements the functions of the above-mentioned embodiments, andthe recording medium which stores the program code constitutes thepresent invention.

A number of various recording mediums for supplying the program code maybe used: for example, a Floppy® disk, hard disk, optical disk,magneto-optical disk, CD-ROM, CD-R, magnetic tape, nonvolatile memorycard, and ROM.

The functions of the above-mentioned embodiments may be implemented, notonly by executing the readout program code by the computer, but also bysome or all of actual processing operations executed by an OS (operatingsystem) running on the computer on the basis of an instruction of theprogram code.

Furthermore, the functions of the above-mentioned embodiments may beimplemented by some or all of the actual processing operations executedby a CPU, or the like, arranged in a function extension board or afunction extension unit, which is inserted in or connected to thecomputer after the program code read out from the recording medium iswritten in a memory of the extension board or unit.

As described above, according to the above embodiments, a profile usedto print a monochrome image with a tincture of user's choice without anycolor deviation may be generated.

As many apparently widely different embodiments of the present inventionmay be made without departing from the spirit and scope thereof, it isto be understood that the invention is not limited to the specificembodiments thereof except as defined in the claims.

The invention claimed is:
 1. A color process method comprising: settinga color adjustment value used to adjust an image signal of intermediatelightness by designating a color using a color map; and converting theimage signal of intermediate lightness excepting black color and whitecolor into a monochrome image signal having a tincture by using the setcolor adjustment value, wherein, in the converting step, converting theimage signal of intermediate lightness using the set color adjustmentvalue, and not converting image signals of white color and black colorusing the set color adjustment value, and wherein at least one of thesetting step and the converting step are executed by using one or moreprocessors.
 2. The method according to claim 1, wherein, in the settingstep, the setting is performed using a user interface.
 3. The methodaccording to claim 1, further comprising: setting a chromaticity changerate used for adjusting change of image quality of a highlight part anda shadow part, wherein, in the converting step, the image signal isconverted further using the chromaticity change rate set in the settingstep.
 4. The method according to claim 3, further comprising:registering the color adjustment value and the chromaticity change rate.5. The method according to claim 1, wherein, in the setting step, adefault value corresponding to the color adjustment value is set inadvance.
 6. The method according to claim 5, wherein the monochromeimage signal having the tincture is printed on a recording medium, andthe default value corresponding to the color adjustment value is set foreach recording medium.
 7. A non-transitory computer-readable medium onwhich is stored a program, for causing a computer to execute the colorprocess method according to claim
 1. 8. The method according to claim 1,further comprising storing the color adjustment value for reuse.
 9. Themethod according to claim 1, wherein the monochrome image signal havingthe tincture is converted for printing by using inks.
 10. A colorprocessing apparatus comprising: a setting unit that sets a coloradjustment value used to adjust an image signal of intermediatelightness by designating a color using a color map; and a conversionunit that converts the image signal of intermediate lightness exceptingblack color and white color into a monochrome image signal having atincture by using the set color adjustment value, wherein, theconversion unit, converting the image signal of intermediate lightnessusing the set color adjustment value, and not converting image signalsof white color and black color using the set color adjustment value. 11.The apparatus according to claim 10, wherein, the setting unit performsthe setting using a user interface.
 12. The apparatus according to claim10, further comprising: a unit that sets a chromaticity change rate usedfor adjusting change of image quality of a highlight part and a shadowpart, wherein the conversion unit converts the image signal furtherusing the set chromaticity change rate.
 13. The apparatus according toclaim 12, further comprising: a registration unit that registers thecolor adjustment value and the chromaticity change rate.
 14. Theapparatus according to claim 10, wherein the setting unit has set adefault value corresponding to the color adjustment value in advance.15. The apparatus according to claim 14, wherein the monochrome imagesignal having the tincture is printed on a recording medium, and thedefault value corresponding to the color adjustment value is set foreach recording medium.
 16. The apparatus according to claim 10, furthercomprising a unit that stores the color adjustment value for reuse. 17.The apparatus according to claim 10, wherein the monochrome image signalhaving the tincture is converted for printing by using inks.
 18. Theapparatus according to claim 10, wherein the color map is atwo-dimensional map.
 19. The apparatus according to claim 10, whereinthe image signals of white color and black color depend on a printpaper.